Sir William D'Oyly, 1st Baronet (ca. 1614 – November 1677) was an English politician who sat in the House of Commons variously between 1654 and 1677. D'Oyly was the son of William D'Oyly. He succeeded to the estates of his uncle Henry, and was known as Sir William, the elder. As heir to Susan D'Oyly, his cousin, he came into possession of Pond-hall (Hadleigh), Topsfield, and Cossford, in Suffolk, and Shottisham (now more generally spelled Shotesham), Gostlings, and three manors in Warham, in Norfolk. He was serving abroad in the army of Gustavus Adolphus of Sweden, and remained abroad after Gustavus Adolphus's death until he returned to take possession of the family fortune. He was knighted by King Charles I in 1642, for his gallant behaviour.